XR16L570 Datasheet, PDF (45/46 Pages) Exar Corporation – SMALLEST 1.62V TO 5.5V UART WITH 16-BYTE FIFO AND POWERSAVE

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REV. 1.0.0
XR16L570
SMALLEST 1.62V TO 5.5V UART WITH 16-BYTE FIFO AND POWERSAVE
TABLE OF CONTENTS
GENERAL DESCRIPTION................................................................................................. 1
APPLICATIONS ............................................................................................................................................... 1
FEATURES ..................................................................................................................................................... 1
FIGURE 1. BLOCK DIAGRAM ............................................................................................................................................................. 1
FIGURE 2. PACKAGE AND PIN OUT (24-PIN QFN PACKAGE).............................................................................................................. 2
ORDERING INFORMATION ................................................................................................................................ 2
PIN DESCRIPTIONS ......................................................................................................... 3
1.0 PRODUCT DESCRIPTION .................................................................................................................... 5
2.0 FUNCTIONAL DESCRIPTIONS ............................................................................................................ 6
2.1 CPU INTERFACE ............................................................................................................................................. 6
FIGURE 3. XR16L570 TYPICAL DATA BUS INTERCONNECTIONS ........................................................................................................ 6
2.2 5-VOLT TOLERANT INPUTS ........................................................................................................................... 7
2.3 DEVICE HARDWARE RESET .......................................................................................................................... 7
2.4 DEVICE IDENTIFICATION AND REVISION .................................................................................................... 7
2.5 INTERNAL REGISTERS ................................................................................................................................... 7
2.6 DMA MODE ...................................................................................................................................................... 7
2.7 INT OUTPUT ..................................................................................................................................................... 7
TABLE 1: INT PIN OPERATION FOR TRANSMITTER............................................................................................................................. 7
TABLE 2: INT PIN OPERATION FOR RECEIVER .................................................................................................................................. 7
2.8 CRYSTAL OR EXTERNAL CLOCK INPUT ..................................................................................................... 8
FIGURE 4. TYPICAL CRYSTAL CONNECTIONS ..................................................................................................................................... 8
FIGURE 5. EXTERNAL CLOCK CONNECTION FOR EXTENDED DATA RATE ............................................................................................ 8
2.9 PROGRAMMABLE BAUD RATE GENERATOR ............................................................................................ 9
FIGURE 6. BAUD RATE GENERATOR AND PRESCALER ....................................................................................................................... 9
TABLE 3: TYPICAL DATA RATES WITH A 14.7456 MHZ EXTERNAL CLOCK.......................................................................................... 10
2.10 TRANSMITTER ............................................................................................................................................. 10
2.10.1 TRANSMIT HOLDING REGISTER (THR) - WRITE ONLY....................................................................................... 10
2.10.2 TRANSMITTER OPERATION IN NON-FIFO MODE ................................................................................................ 10
FIGURE 7. TRANSMITTER OPERATION IN NON-FIFO MODE .............................................................................................................. 11
2.10.3 TRANSMITTER OPERATION IN FIFO MODE ......................................................................................................... 11
FIGURE 8. TRANSMITTER OPERATION IN FIFO AND FLOW CONTROL MODE ..................................................................................... 11
2.11 RECEIVER .................................................................................................................................................... 11
2.11.1 RECEIVE HOLDING REGISTER (RHR) - READ-ONLY .......................................................................................... 12
FIGURE 9. RECEIVER OPERATION IN NON-FIFO MODE.................................................................................................................... 12
FIGURE 10. RECEIVER OPERATION IN FIFO AND AUTO RTS FLOW CONTROL MODE ....................................................................... 12
2.12 AUTO RTS (HARDWARE) FLOW CONTROL ............................................................................................ 13
2.13 AUTO RTS HYSTERESIS ........................................................................................................................... 13
2.14 AUTO CTS FLOW CONTROL ..................................................................................................................... 13
FIGURE 11. AUTO RTS AND CTS FLOW CONTROL OPERATION....................................................................................................... 14
2.15 AUTO XON/XOFF (SOFTWARE) FLOW CONTROL .................................................................................. 15
TABLE 4: AUTO XON/XOFF (SOFTWARE) FLOW CONTROL ............................................................................................................... 15
2.16 SPECIAL CHARACTER DETECT ............................................................................................................... 15
2.17 INFRARED MODE ........................................................................................................................................ 16
FIGURE 12. INFRARED TRANSMIT DATA ENCODING AND RECEIVE DATA DECODING.......................................................................... 16
2.18 SLEEP MODE WITH WAKE-UP INTERRUPT AND POWER-SAVE FEATURE ........................................ 17
2.18.1 SLEEP MODE ........................................................................................................................................................... 17
2.18.2 POWER-SAVE FEATURE ........................................................................................................................................ 17
2.19 INTERNAL LOOPBACK .............................................................................................................................. 18
FIGURE 13. INTERNAL LOOP BACK ................................................................................................................................................. 18
3.0 UART INTERNAL REGISTERS ........................................................................................................... 19
TABLE 5: UART INTERNAL REGISTERS .................................................................................................................................... 19
TABLE 6: INTERNAL REGISTERS DESCRIPTION. SHADED BITS ARE ENABLED WHEN EFR BIT-4=1.......................................... 20
4.0 INTERNAL REGISTER DESCRIPTIONS ............................................................................................ 21
4.1 RECEIVE HOLDING REGISTER (RHR) - READ- ONLY ............................................................................... 21
4.2 TRANSMIT HOLDING REGISTER (THR) - WRITE-ONLY ............................................................................ 21
4.3 BAUD RATE GENERATOR DIVISORS (DLL AND DLM) - READ/WRITE ................................................... 21
4.4 INTERRUPT ENABLE REGISTER (IER) - READ/WRITE ............................................................................. 21
4.4.1 IER VERSUS RECEIVE FIFO INTERRUPT MODE OPERATION ............................................................................. 21
4.4.2 IER VERSUS RECEIVE/TRANSMIT FIFO POLLED MODE OPERATION................................................................ 22
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